Biology subjects

Tasaka, G.-i.

Publications and source records attributed to Tasaka, G.-i..

6 recordsLinked to original sources

bioRxiv2025

Submedius Thalamus Modulates Orbitofrontal Cortex Representations During Maternal Behavior in Mice

The orbitofrontal cortex (OFC) is central to cognitive and social functions, yet its presynaptic partners remain incompletely defined. In female mice, the OFC modulates infant-directed maternal caregiving behaviors essential for offspring survival in an experience-dependent manner. Here, we identify the submedius thalamus (SMT) as a major presynaptic partner of the OFC. Trans-synaptic tracing revealed intensive inputs from both the SMT and mediodorsal thalamus (MD) to OFC layer 5 excitatory neurons. A mouse line Tnnt1-Cre enabled selective targeting of these higher-order thalamic nuclei. Axonal tracing demonstrated complementary projection patterns of SMT and MD across prefrontal regions. Microendoscopic Ca2+ imaging demonstrated pup retrieval encoding in SMT and MD, but only SMT exhibited learning-related plasticity, characterized by enhanced anticipatory responses as acquired maternal behaviors. Projection-specific chemogenetic silencing demonstrated that only SMT modulates OFC activity during pup retrieval. These findings demonstrate SMT as a previously uncharacterized thalamic hub shaping cortical representations of maternal behavior. HighlightsO_LIOFCRbp4 neurons receive strong inputs from higher-order thalamic nuclei (SMT, MD). C_LIO_LISMT and MD show complementary axonal projections across prefrontal cortical cortex. C_LIO_LISMT ensembles encode pup retrieval with experience-dependent plasticity. C_LIO_LISMT inputs selectively modulate pup retrieval representation in OFCRbp4 neurons. C_LI

neuroscience↗

bioRxiv2025

Neural Circuit Remodeling Underlying Enhanced Feeding During Pregnancy in Mice

Pregnancy represents a unique physiological state marked by substantial adaptations influencing both behavior and metabolism1. Alterations have been observed across multiple levels--from changes in cellular morphology, synaptic density, and neuroglial interactions to a brain-wide reduction in gray matter volume2-7. While these adaptations are thought to support offspring survival and promote maternal physiological and psychological well-being8, their functional significance remains largely unresolved. In particular, linking localized synaptic plasticity to a broader brain-wide circuit dynamics has posed a major challenge. Using virus-mediated screening in mice, we investigated the pregnancy-induced remodeling of the presynaptic landscape of paraventricular hypothalamic (PVH) oxytocin neurons, a central hub of maternal physiology9,10. Here we show a selective and reversible elimination of excitatory synaptic inputs from the medial preoptic nucleus to PVH oxytocin neurons, displaying region-, cell-type-, and pathway-specificity. This reduction in excitatory drive attenuated the anorexigenic activity of oxytocin neurons during feeding, thereby promoting the increased food intake characteristic of pregnancy. These data demonstrate that the selective suppression of anorexigenic PVH oxytocin neuron activity plays a critical role in appetite regulation during pregnancy. More broadly, our data identify a pregnancy-associated remodeling of hypothalamic neural circuits with direct physiological relevance.

neuroscience↗

bioRxiv2024

Flexible Adjustment of Oxytocin Neuron Activity in Mother Mice Revealed by Microendoscopy

Oxytocin (OT) neurons in the hypothalamic paraventricular nucleus (PVH) play an important role in a range of physiological and behavioral processes, including the initiation of milk ejection and the regulation of parental behaviors in mothers. However, their activity patterns at the single-cell level remain poorly understood. Using microendoscopic Ca2+ imaging in freely moving mother mice, we demonstrate highly correlated pulsatile activity among individual OT neurons during lactation. The number of OT neurons engaged in the pulsatile activity, along with the characteristics of individual waveforms, was dynamically modulated by lactation and weaning experiences. Notably, only [~]10% of the imaged OT neurons exhibited a significantly elevated response during pup retrieval, a hallmark of maternal behaviors, with a magnitude 18 times smaller than that observed during lactation. Collectively, these findings demonstrate the utility of microendoscopic imaging for PVH OT neurons and highlight the flexible adjustments of their individual activity patterns in freely behaving mother mice.

neuroscience↗

bioRxiv2023

A Prefrontal Neural Circuit for Maternal Behavioural Leaning in Mice

Maternal behaviors, which are crucial for the survival of mammalian infants, require the coordinated operation of multiple brain regions to process infant cues, make decisions, and execute motor plans. Although these processes likely demand higher cognitive functions, the prefrontal areas that regulate limbic parental programs remains poorly understood. Here, we show that the orbitofrontal cortex (OFC) excitatory projection neurons promote alloparental caregiving behaviors in female mice. By chronic microendoscopy, we observed robust yet adaptable representations of pup-directed anticipatory and motor-related activities within the OFC. Some of these plastic responses were significantly overlapped with those related to nonsocial reward signals. The inactivation of OFC output reduced the phasic activities of midbrain dopamine (DA) neurons specifically tied to pup retrieval and impaired the modulation of DA release to the ventral striatum during the acquisition of alloparental behaviors. These findings suggest that the OFC transiently boosts DA activity during the acquisition phase, thereby facilitating the manifestation of alloparental behaviors.

neuroscience↗

bioRxiv2020

Sparse Coding in Temporal Association Cortex Improves Complex Sound Discriminability

The mouse auditory cortex is comprised of several auditory fields spanning the dorso-ventral axis of the temporal lobe. The ventral most auditory field is the temporal association cortex (TeA), which remains largely unstudied. Using Neuropixels probes, we simultaneously recorded from primary auditory cortex (AUDp), secondary auditory cortex (AUDv) and TeA, characterizing neuronal responses to pure tones and frequency modulated (FM) sweeps in awake head-restrained mice. As compared to primary and secondary auditory cortices, single unit responses to pure tones in TeA were sparser, delayed and prolonged. Responses to FMs were also sparser. Population analysis showed that the sparser responses in TeA render it less sensitive to pure tones, yet more sensitive to FMs. When characterizing responses to pure tones under anesthesia, the distinct signature of TeA was changed considerably as compared to that in awake mice, implying that responses in TeA are strongly modulated by non-feedforward connections. Together with the known connectivity profile of TeA, these findings suggest that sparse representation of sounds in TeA supports selectivity to higher-order features of sounds and more complex auditory computations.

neuroscience↗

bioRxiv2020

Motor corollary discharge activates layer six circuits in the auditory cortex

Optogenetic activation of Ntsr1+ layer 6 corticothalamic (L6 CT) neurons modulates thalamocortical sensory processing and perception for hundreds of milliseconds following laser offset. Naturally occurring sources of extrasensory inputs that could recruit L6 CTs prior to upcoming sensory stimuli have not been identified. Here, we found that 100% of L6 CTs in mouse primary auditory cortex (A1) expressed FoxP2, a protein marker found in brain areas that coordinate sensory inputs with movement. To test the idea that motor preparatory inputs could be a natural extrasensory activator of L6 CTs, we combined quantitative videography, optogenetically targeted single unit recordings, and two-photon imaging during self-initiated behavior. We found that A1 L6 CTs were activated hundreds of milliseconds prior to orofacial movements, but not whole-body movements associated with locomotion. These findings identify new local circuit arrangements for routing motor corollary discharge into A1 and suggest new roles for CT neurons in active sensing.

neuroscience↗